a) Field of the Invention
This invention relates to the field of prime mover hydro turbines, specifically describing a means of generating significant amounts of electrical power from man-made canals and other slow natural waterways such as rivers, tidal basins, etc., by manipulating flowing current through, over, and around a buoyant, shaped structure. Dynamic flow through a rotor is accomplished by creating a suction vortex behind the rotor that draws increased pressurized flow through the turbine.
b) Description of the Related Art
Hydropower devices are many, from waterwheels to modern reaction turbines, to the newer hydrokinetic devices which are presently being developed to take advantage of tidal, estuary, river, or canal flow. Recent historical realities are causing us to focusing new attention on the various untapped power resources of the planet so that we might capture an increasing portion of our power needs from renewable resources.
Many of the numerous patented inventions in this class are designed to use ducting and venturi structures to accelerate water through a turbine to increase the kinetic energy density of slow flowing water. Some of these inventions are symmetrical in that they are intended to capture energy from flow in both directions, as in estuary or tidal currents. Some also are intended to be mounted in large banks of identical turbines so that they can capture useful amounts of power from the Gulf Stream or other such meandering undersea currents.
As far back as 1867, Rowe patented a “Water Wheel” U.S. Pat. No. 61,362 which is substantially similar to the prior art in that it places a funnel-like structure within a floating, shaped box so that the flow is concentrated onto paddles in a constricted area at the exit port. This invention is extremely advanced for its time, and it is the first prior art from which modern inventions of this class derive.
There are only a very small number of inventions of this class that attempt to create suction to augment the power factor. Inventions such as Lamont's U.S. Pat. No. 7,147,428, and Parker's U.S. Pat. No. 4,274,009 in particular, do employ suction forces to increase turbine output. Lamont's Hydro Turbine places a converging ring around the downstream output of a turbine-containing tube to lower the back pressure behind the rotor. Mouton's inventions U.S. Pat. Nos. 4,219,303, 4,095,918, 4,166,596, and 3,986,787 all use a form of diffuser-augmented turbine with concatenated nozzles or venturis to accelerate or focus flow, and his duct's outside surfaces are diverging, in contrast to Lamont's converging flow at the exit port. This opposite orientation of these important functional elements illustrates the hydrodynamic debate amongst inventors as to the correct design requirements for reintegrating flow into the mainstream after it leaves the turbine housing.
Finney's Superventuri Power Source, U.S. Pat. No. 5,464,320, describes a multi-stage suction turbine with internally angular elements similar to the present invention. While there are some conceptual similarities with the present invention, there are many more dissimilarities, such as his placement of a blade for capturing energy in the flow path of the last downstream element, while the present invention uses the last downstream element to suck flow out of the first element and thereby induce flow past the rotor, rather than directing manipulated flow onto a blade structure. Finney also does not make use of the outside surfaces of his elements to manipulate or act upon flow, and merely makes them straight as in a tube. It is clear that Finney's invention is not intended for use in water flows, as there is no design element inherent in his device for capturing an incompressible, high-density fluid such as water.
Hesh's U.S. Pat. No. 4,868,408, a Portable water-powered electric generator contains one similar element to the present invention that is not contained in any of the other prior art, and that is a flask-shaped structure behind a constricted port which roughly corresponds to the torpedo-shaped structure at the center of the present invention's shaped bodies. However, Hesh ascribes no function to this element in his patent, and merely describes it as a means for containing a dynamo. It has no other stated purpose, nor does it share any similar function to any component of the present invention.
Salls' Hydrokinetic Generator U.S. Pat. No. 6,472,768B1, is a submersible scoop-like structure with a hollow, tapered inner chamber to funnel flowing water through a turbine. This prior art employs a tapered outer hull to increase flow velocity past the hull with the intent to create lower pressure behind the hull, so that increased flow through the inside of the hull and through the turbine is accomplished. Although Salls' hull can be described as converging/diverging, and common to much prior art of this class, a primary difference in function is that Salls did not consider a secondary hull behind the first to further manipulate flow or to use focused suction forces, as the present invention does.
Parker's U.S. Pat. No. 4,274,009 is the only discovered prior art that uses artificial structures to create a rotary nappe, and alone shares this similarity to the present invention. A nappe is the suction gap created by water flowing over a weir. When a weir is closed to the outside atmosphere, the lowered pressure created by the accelerated flow over the weir sucks water if it is closed to the atmosphere, or sucks air if it is open. Parker places a shroud ring ahead of a torpedo-shaped structure, and natural flow of sufficient velocity causes a suction nappe to be formed on the outer surface of the torpedo structure. There are several distinct differences compared to the present invention. First, Parker's forward structure takes the shape not of a funnel, as in the present invention, but an inverted funnel. His assumption seems to be that the suction nappe will draw sufficient flow through the rather small port of the inlet of his shroud ring to generate useful energy.
Two elements are shared by both the present invention and Parker's device, and that is the use of a torpedo-shaped structure to hold a nappe, and the use of some form of ducting structure ahead of the torpedo to direct flow. However, the two inventions differ substantially in that the present invention employs a funnel and nozzle of differential shape and function to self-create the suction nappe, uses a Kaplan-style hydro propeller on a larger portion of the torpedo, and employs a second stage of ducting and suction to entrain and control flow through a multi-stage, multi-functional conduit. Although the two inventions share the concept of creating a suction nappe, the nappes are produced by different methods, different means, and with a combination of different elements. Parker makes no attempt, for example, to use any of his own means to produce velocity of flow sufficient to produce a nappe, and so his device is dependent upon nature to produce flow of sufficient velocity to build the nappe. The present invention employs a funnel and a nozzle around the torpedo concentrically to produce an artificial flow environment around the torpedo such that the flow velocity required to build and maintain a powerful nappe, is inherent in the invention itself, and in fact is the primary purpose of the present invention's nozzle.
Mouton's River Turbine, U.S. Pat. No. 3,986,787, most closely physically resembles the present invention and a description of the significant differences to the present invention, with a commentary on the technical problems of Mouton's patent, which the present invention overcomes and solves, constitutes a significant portion of the Detailed Description of the Invention below.